Andreas Renschler gestures during the official announcement of the construction of a new Daimler car plant in Sao Paulo October 1, 2013. REUTERS/Paulo Whitaker

“The decision about who will succeed me is not an easy one for the supervisory board,” Winterkorn, whose contract as chief executive runs until 2016, was quoted as saying.

Both Renschler and Diess were in the running, the magazine said on Wednesday.

“Both colleagues are managers who did good work in their previous jobs, otherwise we would not have hired them,” Winterkorn told the magazine, adding that internal candidates were also regarded as potential leaders.

“A Volkswagen boss has to have a big affinity to our products. He needs to be close to customers, and he needs to have a relationship to dealers,” the magazine quoted Winterkorn as saying.

“And he has to have a certain level of social acceptance within the company. Like always it depends on the personality,” Winterkorn said. It also helps if the candidate is an engineer, he added.

Asked whether he could imagine carrying on another four years, Winterkorn said: “Who knows. My contract ends in 2016, and it depends on the situation. Four years ago I could not have imagined working until I am 69.”